Satish C. Mohleji

A route-oriented planning and control concept for efficient flight operations at busy airports

Abstract A route-oriented planning and control (ROPAC) concept defines minimum time paths for aircraft, dynamically adjusts traffic flow rates to maximize airport capacity, and employs speed control to separate aircraft. Precise landing sequences and times are established using non-intersecting flight paths and pairwise aircraft separation requirements. Projections of desired aircraft positions relative to their current locations and timely speed commands are displayed to the operators to take control actions for aircraft safety. Operational analysis results show substantial reduction in delays, fuel penalties and air/ground communications with ROPAC design.

Use of the departure enhanced planning and runway/taxiway assignment system (DEPARTS) for optimal departure scheduling at busy airports

The DEPARTS research project has developed a laboratory simulation model to develop and evaluate optimization models that can be used in future surface traffic management systems. Operational benefits of different modeling approaches can be evaluated over several days of simulated operation using desired performance metrics. Research also shows a significant benefit in improving the current accuracy of push-back time estimates. The objective of DEPARTS research is to develop computer algorithms that could be incorporated into future surface traffic management systems, and to build a research tool that can be used to simulate different surface traffic management operational concepts in the laboratory.

Future vision of globally harmonized national airspace system with concepts of operations beyond year 2020

As laid out in the National Airspace Systems (NAS) Operational Evolution Plan (EOP), the Federal Aviation Administration (FAA) and the aviation community are planning to make significant investment in NAS improvements over the next ten years. These enhancements involve implementation of communication, navigation and surveillance (CNS) technologies, and automation of ground systems in order to improve efficiency, safety, capacity and security. However, the mode of operations during this time frame is expected to continue as it is today. A number of research efforts are underway to consider significant changes to NAS operations beyond the OEP. This paper presents a vision of year 2020 and beyond based on a number of new paradigms that provides a globally harmonized service to conventional aircraft, uninhabited and space-launch vehicles. The key paradigms are: 1) a multi-faceted airport structure of well connected hubs, spoke, satellite and smaller airports; 2) multi-level CNS architecture for seamless and secured operations; 3) problem-free flight planning independent of look ahead times; 4) flexible sector boundaries based on equitable workload; and 5) a universal information service assuring uniformity and security of real time information to all stakeholders and service provider decision support systems (DSS). Potential make up of future air traffic is discussed including a significant number of non-scheduled flights such as on-demand service, charter, ravel club, fractional and short-haul intra-city operations. A concept of system wide information management (SWIM) that provides a virtual electronic collaboration space is described. The operational concepts fully support self-delivery and self-separation for appropriately equipped aircraft. New roles for service providers at national, regional and local air traffic

Performance analysis of North Pacific Operations using an automated air traffic control system simulation

A computer simulation is described which models current and future air-traffic control (ATC) system operating environments, including traffic demands, route structures, winds, and separation criteria. Metrics are defined to highlight parameter sensitivities for optimizing direct operating costs, and to provide an assessment of performance in terms of time and fuel penalties under suboptimum operating conditions. The analysis results are intended to help the designers of the future North Pacific (NOPAC) system increase airspace capacity and operational efficiency. Requirements are established for further research to automate ATC functions for future real-time closed-loop control of aircraft over the ocean. >

A process for estimating cost/benefits of future air transportation system operational concepts based on 4D navigation

The aviation community worldwide has been working for sometime to define a vision of the future air transportation system. The overall progress thus far has been primarily at a conceptual stage. This paper integrates a number of operational concepts into a realizable vision for the National Airspace System (NAS). A process is defined to help develop future operational scenarios based on the makeup of year 2020 fleet mix and aircraft avionics capabilities, considering non-scheduled on-demand, charter, travel club, fractional and short-haul intra-city operations. A majority of aircraft are projected to be able to fly via 4D navigation and to assume a larger share of the responsibility for maintaining separation. This would require significant investment in avionics and the automation of the ground system and infrastructure. Cost/benefits analysis is a key portion of the process. Example results are presented to illustrate return on investment over time as more and more aircraft are equipped with enhanced avionics. The operational benefits of 4D navigation operations are derived from reduced air and ground delays determined from the NAS-wide simulation of future operations. The example presented compared the life cycle costs of air/ground enhancements as function of aircraft equipage to ascertain that the overall benefits outweigh the implementation costs over time. The process is based on a number of operational assumptions and likely air/ground system enhancements beyond the currently planned enhancements over next 10 years. The evaluation process presented in the paper can be used to help understand the benefits and limitations of the future operational concepts, and intends to help define an ideal, but realistic vision of the future air transportation system for guiding research cost effectively.

Flight management systems information exchange with AERA to support future air traffic control concepts

A goal of the future air traffic control (ATC) system is to permit aircraft to fly according to their preferences (e.g., direct routes and optimum altitudes). Towards this goal, advanced automated en route ATC (AERA) concepts are currently in the research and development phase to provide a gradual evolution of ATC automation capabilities. The airborne flight management systems (FMSs) can provide accurate information on aircraft states needed to meet the automation objectives of advanced AERA concepts. The impact of user-preferred flight paths and altitudes on future ATC operations is analyzed. The results highlight potential fuel savings for the airspace users. Air/ground functional integration and information flow are discussed to minimize data ambiguities, and to reduce duplication of data in the airborne and ground computers. Computer/human interface requirements are also addressed. Key technical issues which must be addressed in order for the ground system to support flexible use of airspace, and increase system capacity in a diverse mix of aircraft operations are identified. The results presented show that FMS-equipped aircraft could realize significant fuel savings if permitted to fly preferred altitudes using step climbs.<<ETX>>

Optimizing Flight Paths for RNP Aircraft in Busy Terminal Areas - First Step Towards 4-D Navigation

The next generation air transportation system (NGATS) concepts, defined by the Joint Planning and Development Office (JPDO), consider 4D navigation as one of the core elements. During intervals of heavy traffic, establishing and achieving 4D operations for arrivals in busy terminal areas will be a major challenge. This paper presents the development and demonstration of a decision support tool called logical expansion of arrivals and departures to enhance RNP (required navigation performance) (LEADER). This human-in-the-loop simulation tool (with controller, pilot and traffic management coordinator (TMC) workstations) permits each aircraft, based on its capabilities, to fly desired 3D flight paths (shortest flight paths with continuous descent) under varying wind conditions. A flexible terminal area route structure is developed that eliminates all traffic merge points prior to the traffic converging on to the final approaches. The design of the tool is based on minimizing the variations between the aircraft flight planning and actual operations by defining routes all the way to touchdown and establishing landing schedules using accurate flight time estimates and pair-wise wake vortex separations. Traffic under high density conditions at a major airport during instrument meteorological conditions (IMC) was simulated. The results show significant savings in distance traveled and flight times, as well as a reduction in air/ground communications that would provide reduced operating costs for the users and lower workload for the operators. On an average, the flights saved 10.94 nmi in distance flown, 2 minutes and 16 seconds in flying time and reduced air/ground communications by 30 percent. Since the terminal areas involve most complex traffic patterns due to continuously climbing and descending flights, the tool offers a foundation and a first step towards realizing the future goal of using 4D navigation from end to end in the entire National Airspace System (NAS)

Air traffic control automation concepts to optimize flight management system utilization

The author defines the requirements and design philosophy for developing ground-based automation planning and control advisory concepts to best serve the aircraft with FMS (flight management system) capabilities. Analytical results are presented, based on comparison of operational data with the user-preferred trajectories to identify flying-time variabilities in various segments of arriving flights. En route descents, terminal maneuvering areas, and the final approaches are considered to determine the impact of aircraft and environmental factors on flying times essential for traffic planning. Simple time-estimation algorithms based on FMS-defined speed schedules and prevailing winds are presented for estimating flying times during en route descents. Automation planning and control concepts are developed which utilize flexible route structures and a speed-control strategy to permit the aircraft maximum use of FMS and onboard avionics in all operating conditions.<<ETX>>

A Route Oriented Planning and Control Concept for Efficient Flight Operations at Busy Airports

Abstract A Route Oriented Planning and Control (ROPAC) concept defines minimum time paths for aircraft; dynamically adjusts traffic flow rates to maximize airport capacity; and employs speed control to separate aircraft. Precise landing sequences and times are established using non-intersecting flight paths and pairwise aircraft separation requirements. Projections of desired aircraft positions relative to their current locations and timely speed commands are displayed to the operators to take control actions for aircraft safety. Operational analysis results show substantial reduction in delays, fuel penalties and air/ground communications with ROPAC design.

Modeling the effect of pressure altimetry on geostationary satellite surveillance accuracy

In the ranging and processing mobile-satellite (RAPSAT) system, aircraft position is estimated from the aircraft altitude in conjunction with the aircraft range (signal transit time) to two surveillance satellites. Due to large variations in atmospheric conditions, altimeter readings deviate significantly from the true geometric altitudes. As a result, the aircraft position estimation accuracy of satellite surveillance systems, such as RAPSAT, may be degraded. The authors model the spatial and temporal deviations between pressure altitudes and true geometric altitudes, and the results are applied to characterize the position estimation error of the RAPSAT system. The results show that the geometric altitude deviated widely from the pressure altitude at different latitudes and altitudes, but the altitude difference remained constant at the same latitudes and altitudes. As a result, these altitude deviations can be modeled as a constant correction over the same latitudes and altitudes. These altitude deviations were observed to be reasonably stable over several days. With the adjustment of altimeter readings, the errors in the estimation of geometric altitudes, including instrumentation errors, were computed to be less than 310 ft (one standard deviation) across conterminous US. The corresponding root mean square error in aircraft position (2-D) estimated by the RAPSAT system varied from 135 ft to 297 ft for six selected locations representing the cross section of the country.<<ETX>>